EVIDENCE FOR INCREASES IN ANTARCTIC BLUE WHALES BASED ON BAYESIAN MODELLING

摘要: Antarctic blue whales (Balaenoptera musculus intermedia) are the largest and formerly most abundant whale subspecies, but were hunted to near extinction last century. Estimated whaling mortality was unsustainable from 1928 1972 (except during 1942–1944), depleting them 239,000 (95% interval 202,000–311,000) a low of 360 (150–840) in 1973. Obtaining statistical evidence for subsequent increases has proved difficult due their scarcity. We fitted Bayesian models three sighting series (1968–2001), constraining maximum rates increase 12% per annum. These indicated that increasing at mean rate 7.3% annum (1.4%–11.6%). Informative priors based on biology (4.3%, SD = 1.9%) hierarchical meta-analysis other populations (−3%, 11.6%), suggest plausible lower (although latter wide intervals), mysticetes obtains similar (6.7%, 4.0%). Possible biases affecting input abundance estimates discussed. Although appear have been since Sovier illegal ended 1972, they still need be protected-their estimated 1996 population size, 1,700 (860–2,900), just 0.7% (0.3%–1.3%) pre-exploitation level.